This application is based on Japanese Patent Application Nos. 10-107789 and 10-170068 filed in Japan, the contents of which are hereby incorporated by reference.
The present invention relates to a sheet processing device to sort and discharge a sheet on which an image is formed, and an image forming system including this sheet processing device and an image forming apparatus.
In an image forming apparatus including a conventional sheet processing device, there are cases when a plurality of users share one printer. In order to prevent a subsequent printed sheet from being mixed up at the sheet discharge unit, a sensor is provided to detect the presence of a sheet corresponding to each of a plurality of discharge bins to select an appropriate discharge bin to discharge a sheet.
Such a printer is limited in the number of the discharge bins. When a sheet is discharged and left at all the discharge bins, discharge of another sheet will cause that sheet to be mixed up with the sheet already left on any of the discharge bins.
As an image forming apparatus including such a sheet processing device, the technique disclosed in Japanese Patent Laying Open Nos. 8-9169, 6-92538, and 8-20457 is known.
According to the technique disclosed in Japanese Patent Laying-Open No. 8-9169, a sheet will be discharged to a particular discharge unit when all the discharge bins have sheets output therein. However, the problem of a newly output sheet being mixed up with the sheet left on the discharge bin will not be solved. This is inconvenient for the user. The operability in discharging a sheet is not satisfactory.
According to the technique disclosed in Japanese Patent Laying-Open Nos. 6-92538 and 8-20457, the position of the discharge bin is shifted to the left and the right to easily identify the interval between a job (one set of a series of printing process for a group of original documents). However, such a structure will increase the cost, and mixture of the discharge sheets cannot be avoided even when the output sheets are shifted and mounted for every job at the discharge bin. Furthermore, the interval between the jobs cannot be easily detected at a glance even when shifting is carried out on the discharge bins arranged in the vertical direction. This may cause the user inconvenience. The operability in discharging a sheet is not of the satisfactory level.
It is to be noted that the capacity of storing sheets in the bin of the sheet output device (bin capacity) is limited. The sheet output must be suppressed during the operation when the bin capacity has come to its limit.
A sheet output device is proposed to continue the sheet output at another bin when the capacity of the current bin arrives at its limit. When sheets are output into separate plurality of bins, there is a possibility that not all the sheets may be collected. The user may forget about the other sheets in another bin. There is a problem that, not only the operability of the user specifying the current sheet output, but also the operability of other users, will be degraded.
In view of the foregoing, an object of the present invention is to provide a sheet processing device improved in operability, connected to an image forming apparatus.
Another object of the present invention is to prevent sheets discharged corresponding to a plurality of image forming jobs, if any, from being mixed up at the discharge unit in a sheet processing device connected to an image forming apparatus.
A further object of the present invention is to prevent a discharged sheet of another job from being mixed up when the number of the sections where sheets are discharged corresponding to a plurality of image forming jobs, if any, is limited and all the sections are occupied by one job in a sheet processing device connected to an image forming apparatus.
Still another object of the present invention is to provide a sheet processing device improved in operability.
A still further object of the present invention is to provide an image forming system including an image forming apparatus and a sheet discharge device connected thereto and improved in operability.
The above objects can be achieved by a sheet processing device that processes a discharge sheet.
According to an aspect of the present invention, a sheet processing device which processes sheets discharged from an image forming apparatus executing a print job, includes: a first discharge tray; a plurality of second discharge trays; a plurality of sensors which detects whether there is a sheet on each of the plurality of second discharge trays, a transport unit which transports a bundle of sheets from the second discharge tray to the first discharge tray; and a controller which controls the transport unit so that, when detection is made of a sheet on all the second discharge trays by the sensor at the time of discharging a sheet by a new job, at least one of second discharge trays is selected according to a predetermined condition to transport a bundle of sheets from the selected second discharge tray.
When the sensor detects that sheets are discharged at all the plurality of second discharge trays in the event of discharging a sheet according to a new process job, a second discharge tray is selected according to a predetermined condition. The sheet already discharged on the selected second discharge tray is transported onto the first discharge tray. The sheet output from the new process job is discharged onto the second discharge tray from which the sheet has been removed.
Accordingly, a second discharge tray on which a sheet is not placed is prearranged. A sheet is discharged corresponding to the new job onto the prearranged second discharge tray. Therefore, the sheet output corresponding to a new job will not be mixed up at the discharge tray. Thus, the operability of the device is improved.
According to another aspect of the present invention, a sheet processing device includes: a first discharge tray; a plurality of second discharge trays; a plurality of timers which count the time of a bundle of sheets left on each of the plurality of second discharge trays; a transport unit which transports the bundle of sheets discharged on the second discharge tray to the first discharge tray; and a controller which controls the transport operation of the transport unit according to the count result of the timers. The bundle of sheets discharged on the second discharge tray is transported to the first discharge tray according to the time of the bundle of discharged sheets left at the plurality of second discharge trays. As a result, the bundle of sheets left for a long period are discharged to the first discharge tray, and the second discharge tray is prepared for a new job.
According to a further aspect of the present invention, a sheet processing device which processes sheets discharged from an image forming apparatus that executes a print job, includes: a memory which stores identification information of a user requesting a job corresponding to a plurality of jobs; a first discharge tray; a plurality of second discharge trays; a transport unit which transports to the first discharge tray a bundle of sheets discharged on the second discharge tray; and a controller which controls the transport unit so that a bundle of sheets of a previous job is transported from a second discharge tray when the user of a new job differs from the user of the previous job at the time of discharging a sheet by the new job to that second discharge tray from which the sheet of the previous job has been discharged.
When a sheet according to a newly processed job is to be discharged onto a second discharge tray in which a sheet is already discharged according to the detection by the sensor, the sheet according to the newly processed job is discharged onto the second discharge tray on which a sheet is already discharged when the user processing the new job is the same user processing the previous job corresponding to the sheet already discharged on the second discharge tray, and the sheet already discharged on the second discharge tray is transported to the first discharge tray so that the sheet according to the newly processed job is discharged onto that second discharge tray from which the sheet has been removed by the transportation when the user processing the new job differs from the user processing the previous job corresponding to the sheet already discharged on the second discharge tray.
Thus, a second discharge tray on which no sheet is placed is prearranged. A sheet corresponding to a new job is discharged onto the prearranged second discharge tray. The sheet output corresponding to the new job will not be mixed up at the discharge sheet unit. Thus, the operability of the device is improved.
According to still another aspect of the present invention, a sheet processing apparatus includes: a first discharge tray; a plurality of second discharge trays; a detector which detects a state that a sheet cannot be discharged to at least one of the plurality of second discharge trays; a transport unit which transports a bundle of sheets discharged on the second discharge tray to the first discharge tray; and a controller which controls the transport operation of the transport unit according to a detect result of the detector.
Detection such as capacity overflow is made for at least one of the plurality of second discharge trays. A sheet is transported to the first discharge tray according to the detection. Thus, a sheet processing device improved in operability can be provided.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.